PROPAGATION - by AD5Q HOUSTON, TEXAS -- AUGUST 1998


Midsummer typically does not offer many options for the DXer. 20 Meters is in great shape, but higher bands suffer from low daytime MUFs because the ionosphere is exposed to too much direct sunlight. We look forward to improved conditions on 15 & 10 in the fall, and work the night paths on 20. This not the peak season for any daypath bands.

There is, however, and interesting development that bodes well for the fall season on 10 Meters: the solar flux has climbed above 150 for the first time in the new cycle. Recent months have brought peak flux values around 130, which is good enough to open 10 to most of Europe in the fall. But parts of the world would remain inaccessible because higher flux levels are required to open paths across high latitudes, such as to Russia from Texas. With fluxes above 150 we will get these DX windows in the morning, and 10 Meters will be wall-to-wall with DX for the first time in a few years. Eventually the flux will be above 150 most of the time, and we will take these openings for granted. This fall they will be a novelty, and draw a great deal of attention and activity. Paths directly over the pole will still likely be difficult, but not on 15. A flux of 150 makes the whole world accessible on 15.

For now, most activity is on 20 and good conditions also exist on 17. On 20 the formula for DX propagation is simple: virtually any night path is open, and these openings extend to regions where the sun is low in the sky (late afternoon, early morning, or in the southern hemi-sphere where it is winter). Antarctic long paths are not in season, so most contacts into southern Asia must be made via the north. Conditions on 20 are really excellent, and a flux of 150 ensures that this band will be open all night. 17 is also open late.

Conditions on 15 are not that good, though it did sound like the east coast had broad windows into Europe during the WAE. From Texas, signals were mostly weak. On 10, South Americans were heard running Europe nicely on the north/south path - and some of these Europeans were copyable from Texas.

We will be out of the summer doldrums shortly. September is a month of radical improvement on daypath bands, and October will be really awesome unless impaired by solar storms. For now, enjoy the great nightpaths on 20.

http://www.nol.net/~ids/prop.html
E-Mail: ad5q@kb5tes.#setx.tx.usa.na or ids@nol.net